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MEDIUM: quic: Limit the number of ACK ranges

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When building a packet with an ACK frame, we store the largest acknowledged
packet number sent in this frame in the packet (quic_tx_packet struc).
When receiving an ack for such a packet we can purge the tree of acknowledged
packet number ranges from the range sent before this largest acknowledged
packet number.
This commit is contained in:
Frédéric Lécaille 2022-03-15 18:44:20 +01:00 committed by Amaury Denoyelle
parent 8f3ae0272f
commit 141982a4e1
2 changed files with 61 additions and 5 deletions
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11
include/haproxy/xprt_quic.h
View File

@ -991,6 +991,17 @@ static inline void quic_pktns_init(struct quic_pktns *pktns)
pktns->flags = 0;
}
/* Returns the current largest acknowledged packet number if exists, -1 if not */
static inline int64_t quic_pktns_get_largest_acked_pn(struct quic_pktns *pktns)
{
struct eb64_node *ar = eb64_last(&pktns->rx.arngs.root);
if (!ar)
return -1;
return eb64_entry(&ar->node, struct quic_arng_node, first)->last;
}
/* Discard <pktns> packet number space attached to <qc> QUIC connection.
* Its loss information are reset. Deduce the outstanding bytes for this
* packet number space from the outstanding bytes for the path of this

55
src/xprt_quic.c
View File

@ -1559,6 +1559,40 @@ static inline void free_quic_tx_pkts(struct list *pkts)
}
}
/* Remove already sent ranges of acknowledged packet numbers from
* <pktns> packet number space tree below <largest_acked_pn> possibly
* updating the range which contains <largest_acked_pn>.
* Never fails.
*/
static void qc_treat_ack_of_ack(struct quic_pktns *pktns,
int64_t largest_acked_pn)
{
struct eb64_node *ar, *next_ar;
struct quic_arngs *arngs = &pktns->rx.arngs;
ar = eb64_first(&arngs->root);
while (ar) {
struct quic_arng_node *ar_node;
next_ar = eb64_next(ar);
ar_node = eb64_entry(&ar->node, struct quic_arng_node, first);
if ((int64_t)ar_node->first.key > largest_acked_pn)
break;
if (largest_acked_pn < ar_node->last) {
eb64_delete(ar);
ar_node->first.key = largest_acked_pn + 1;
eb64_insert(&arngs->root, ar);
break;
}
eb64_delete(ar);
pool_free(pool_head_quic_arng, ar_node);
arngs->sz--;
ar = next_ar;
}
}
/* Send a packet ack event nofication for each newly acked packet of
* <newly_acked_pkts> list and free them.
* Always succeeds.
@ -1575,6 +1609,12 @@ static inline void qc_treat_newly_acked_pkts(struct quic_conn *qc,
qc->path->in_flight -= pkt->in_flight_len;
if (pkt->flags & QUIC_FL_TX_PACKET_ACK_ELICITING)
qc->path->ifae_pkts--;
/* If this packet contained an ACK frame, proceed to the
* acknowledging of range of acks from the largest acknowledged
* packet number which was sent in an ACK frame by this packet.
*/
if (pkt->largest_acked_pn != -1)
qc_treat_ack_of_ack(pkt->pktns, pkt->largest_acked_pn);
ev.ack.acked = pkt->in_flight_len;
ev.ack.time_sent = pkt->time_sent;
quic_cc_event(&qc->path->cc, &ev);
@ -5006,7 +5046,7 @@ static int qc_do_build_pkt(unsigned char *pos, const unsigned char *end,
struct quic_frame ack_frm = { .type = QUIC_FT_ACK, };
struct quic_frame cc_frm = { . type = QUIC_FT_CONNECTION_CLOSE, };
size_t ack_frm_len, head_len;
int64_t largest_acked_pn;
int64_t rx_largest_acked_pn;
int add_ping_frm;
struct list frm_list = LIST_HEAD_INIT(frm_list);
@ -5036,9 +5076,9 @@ static int qc_do_build_pkt(unsigned char *pos, const unsigned char *end,
goto no_room;
end -= QUIC_TLS_TAG_LEN;
largest_acked_pn = HA_ATOMIC_LOAD(&qel->pktns->rx.largest_acked_pn);
rx_largest_acked_pn = HA_ATOMIC_LOAD(&qel->pktns->rx.largest_acked_pn);
/* packet number length */
*pn_len = quic_packet_number_length(pn, largest_acked_pn);
*pn_len = quic_packet_number_length(pn, rx_largest_acked_pn);
/* Build the header */
if ((pkt->type == QUIC_PACKET_TYPE_SHORT &&
!quic_build_packet_short_header(&pos, end, *pn_len, qc, qel->tls_ctx.flags)) ||
@ -5137,8 +5177,12 @@ static int qc_do_build_pkt(unsigned char *pos, const unsigned char *end,
if (!quic_packet_number_encode(&pos, end, pn, *pn_len))
goto no_room;
if (ack_frm_len && !qc_build_frm(&pos, end, &ack_frm, pkt, qc))
goto no_room;
if (ack_frm_len) {
if (!qc_build_frm(&pos, end, &ack_frm, pkt, qc))
goto no_room;
pkt->largest_acked_pn = quic_pktns_get_largest_acked_pn(qel->pktns);
}
/* Ack-eliciting frames */
if (!LIST_ISEMPTY(&frm_list)) {
@ -5201,6 +5245,7 @@ static inline void quic_tx_packet_init(struct quic_tx_packet *pkt, int type)
pkt->pn_node.key = (uint64_t)-1;
LIST_INIT(&pkt->frms);
pkt->next = NULL;
pkt->largest_acked_pn = -1;
pkt->refcnt = 1;
}